Acute Leukemias

• What does the term "leukemia" derive from?

  Greek words for "white" and "blood"
• What characterizes acute leukemia?

  Rapid clonal proliferation of progenitor cells
• What are the progenitor cells involved in acute leukemia?

  Lymphoblasts and myeloblasts
• What are the known causes of acute leukemia?

  • Most causes are unknown
  • Certain toxins and radiation
  • Exposure to organic solvents like benzene
  • Stepwise progression of mutations in genes
• What are the classification schemes for acute leukemias?

  • FAB classification
  • WHO classification
  • Morphologic examination
  • Cytochemical stains
  • Chromosomal translocations/genetic findings
• What is required for the diagnosis of acute leukemias?

  At least 20% blasts in bone marrow
• What percentage of childhood cancers does acute lymphoblastic leukemia (ALL) represent?

  25%
• How does the risk of ALL change with age?

  Risk increases with age
• What are the common presentations of B cell ALL?

  • Fatigue (anemia)
  • Fever (neutropenia and infection)
  • Mucocutaneous bleeding (thrombocytopenia)
• What are the common presentations of T cell ALL?

  • Similar to B cell ALL
  • May have a large mass in the mediastinum
  • Compromise of regional structures
• What is the WHO classification for ALL?

  • B-lymphoblastic leukemia/lymphoma
  • T-ALL
  • Subdivided into nine subtypes
• What is the most common morphologic type of lymphoblast in ALL?

  Small lymphoblast
• What are the characteristics of small lymphoblasts?

  Scant blue cytoplasm and indistinct nucleoli
• What are the characteristics of larger lymphoblasts?

  Prominent nucleoli and nuclear membrane irregularities
• What is immunophenotyping used for in ALL?

  • Identifies T cell and B cell lineages
  • Both usually express CD34, TdT, and HLA-DR
  • Four subtypes identified by immunologic methods
• What is the most common type of leukemia in adults?

  Acute myeloid leukemia (AML)
• What are the common presentations of AML?

  Myeloblasts in blood, anemia, thrombocytopenia
• What are the subtypes of AML according to the 2017 WHO Classification?

  • Categorized by recurrent cytogenetic abnormalities
  • New entities included
  • Based on primary cytogenetic aberrations
• What is the translocation associated with AML with t(8;21)?

  RUNX1/RUNX1T1
• What is the prognosis for AML with t(8;21)?

  Favorable, unless additional abnormalities occur
• What is the translocation associated with AML with inv(16)?

  CBFB-MYH11
• What is the treatment for acute promyelocytic leukemia?

  All-trans-retinoic acid (ATRA)
• What is a characteristic of acute promyelocytic leukemia (APL)?

  Characterized by a differentiation block at promyelocytic stage
• What is the translocation associated with AML with t(9;11)?

  KMT2A (MLL)-MLLT3
• What are the characteristics of AML with t(9;11)?

  Increased monoblasts and immature monocytes
• What characterizes AML, not otherwise specified?

  • Does not fit WHO subtypes
  • Grouped by morphology and flow cytometry
  • Limited cytochemical reactions
• What are the characteristics of FAB M0 AML?

  Blasts are CD13+, CD33+, CD34+, CD117+
• What is the staining result for FAB M0 AML?

  MPO and SBB stains negative
• What are the characteristics of FAB M1 AML?

  Blasts are CD13+, CD33+, CD34+, CD117+
• What is the staining result for FAB M1 AML?

  At least 3% of blasts positive for MPO and SBB
• What are the characteristics of FAB M2 AML?

  More than 20% blasts, at least 10% maturing cells
• What are the characteristics of FAB M3 AML?

  More than 30-50% promyelocytes
• What are the symptoms associated with FAB M3 AML?

  Severe bleeding, hepatomegaly, DIC
• What are the characteristics of FAB M4 AML?

  More than 20% monocytic cells, more than 30% myeloblasts
• What are the CD markers for FAB M4 AML?

  CD13, CD33, CD14, CD64
• What are the characteristics of FAB M5 AML?

  More than 30% monoblasts, nonspecific esterase positive
• What is the common association with FAB M5 AML?

  Can be associated with t(9;11)
• What are the characteristics of FAB M6 AML?

  More than 80% of BM cells are erythroid
• What is the clinical course of FAB M6 AML?

  Aggressive and rapid clinical course
• What are the characteristics of FAB M7 AML?

  More than 50% of blasts are megakaryocytic